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- M. MANNESMANN.

MANUFAGTURE 0F SEAMLESS TUBES. No. 361,959'. Patented Apr. 26,'1887.

UNITED STATES PATENT OFFICE.

MAX MANNESMANN, OE REMSCHEID, GERMANY.

MANUFACTURE OF SEAMLESS TUBES.

SPECIFICATION forming part of Letters Patent No. 361,959, dated April 26, 1887.

Application filed April 1, 1887. Serial No.

To all whom it may concern:

Be it known that I, MAX MANNEsMANN, of Remscheid, Germany, have invented certain Improvements in the Manufacture of Iron or Steel Tubes, of which the following is a specification.

This invention relates to a process of and apparatus for successively performing the two operations, first, of forcing a solid steel or iron blank which has been suitably heated to assume the form of a tube, and, secondly, of enlarging the size of the tube so formed.

The apparatus consists, essentially, of a pair of approximately barrelshaped rolls, the vertical planes of the axes of which are arranged upon opposite sides of the axial line of a conical or cohoidal mandrel, with their axes inclined relatively in opposite directions. The conical or conoidal mandrel projects part way between the rolls, and is slightly less acute than the angle of divergence of the tapering ends of the rolls between which it is placed. A solid blank fed into the end of the space between the rolls opposite that into which the conical or conoidal mandrel projects is first transformed into a tube by the action upon it of the converging working-faces of the rolls, according to the method described in the pending application of Max Mannesmann, serially numbered 227,087. The tube thus formed is by the continued action of the rolls carried against and over the surface of the mandrel, upon which it is compressed by the divergi ng portions of the working-faces of the rolls, and is thereby made to acquire an increase in both internal and external diameter, with such thickness of shell as may result from the dstance between those portions of the working faces of the rolls which are nearest to the sur face of the mandrel.

The employment of approximately barrelshaped rolls in combination with a conical mandrel for transforming a solid blank of soft metal into a tube of larger diameter than the width of the narrowest part of the space between the working-faces of the rolls is described in Max Mannesmanns pending appli-- cation, serially numbered 233,247 but in that case the pointed end of the mandrel 1s per- 5o mitted to touch or nearly touch the central 233,244. (Model.) Patented in Belgium August 14, 1886, No. 5l,857.

portion of the blank, to which there is no objection when operating upon comparatively soft and ductile metals or alloys, but which is fatal to the practical, successful working of the apparatus when employed to operate on iron or steel blanks which are required to be so highly heated to fit them to be operated upon that the pointed end of the mandrel would be destroyed were it permitted to come in contact with the interior portion of the blank. In the present case, therefore, the rolls are so proportioned and adjusted that the tubular formation is fully developed by the preliminary action of the rolls, so that as the blank progresses the point of the mandrel enters into an aperture in thecenter of the blank of such considerable diameter and length that the pointed end of the mandrel is not brought near enough to the hot metal to be destroyed. It will' therefore be understood that the present invention does not embrace, broadly, the combination of barrel-shaped rolls with a conical mandrel for the purpose of transforming asolid blank into a tube, and then enlarging the tube thus formed,but consists in such a combination of barrel-shaped rolls and a conical mandrel that by the preliminary action of the rolls the tubular formation is fully developed from the solid blank before the tube-enlarging operation is commenced.

As diagonal rollingmachines are well known, it is deemed'sufficent to herein show and describe only those portions of the apparatus which in their construction and mode of operation are comprehended in the present invention.

The drawings are as follows: Figure lis a top view of a pair of barrel-shaped rolls, the axes of which are inclined in relatively opposite directions from the horizontal plane of the axis of a conical mandrel. projecting into the space between the rolls; also show- 4 ing in horizontal section a solid metallic blank which has so far progressed into the space between thc rolls at the end opposite to that into which the mandrel projects that its forward portion has acquired a tubular formation. Fig. 2 is a top view of the apparatus, similar to that shown inlFig. 1, but representing the blank at a further stage of its progress, at which the IOO shell of the tubular formation has begun to bc compressed upon the surface of the mandrel.

Fig. 3 is a similar view of the apparatus, showing the fully-formed enlarged tube issuing at the end of the space between the rolls into which the conical mandrel projects.

For the sake of clearness of description, it is assumed that the two barrel-shaped rolls A a (shown in the drawings) are arranged on either side of the axial line of a conical or y conoidal mandrel, B, the axis of which is horizontal, and that the vertical planes of thc axes of the rolls are parallel with each other and with the axial line of the mandrel, but areinclined from the horizontal plane in relatively opposite directions to such an extent as to approximately proportion the stretching effect which they exert upon the blank, owing to the diagonal direction in which they act, to the amount of reduction of the diameter of the blank which is effected during its passage between the converging portions A a of the Working-faces of the rolls for the purpose of developing in the portion of the solid blank C, upon which their ,preliminary action takes place, a tubular formation according to the method described in the'said pending application of Max Mannesmann, serially numbered 229,087.

By the preliminary action of the rolls upon the blank the tubular formation C is fully developed in the forward portion of the blank by the time it has progressed far enough to acquire contact with the surface of the mandrel, in consequence of which, as will be seen,

the pointed end of the mandrel enters an aperture of considerable diameter, and is thereby prevented from touching the hot blank. As the blank continues its progress, its shell is gradually diminished in thickness by compression between the surface of the mandrel and the diver-ging portions A2 a2 of the working-faces of the rolls, which also act, respectively, in relatively opposite diagonal directions and co-operate with the converging portions A a of the working-faces of the rolls in imparting the endwise movement to the metal of the blank by which it is carried over the base of the conical mandrel and transformed into a tube, C2, the interior diameter of which is determined by the' diameter of the largest part of the mandrel, and the thickness of the shell of which is determined by the distance between the largest part of the mandrel and the adjacent portions of the working-faces of the rolls, respectively.

/Vhen there is a suitable reduction in the thickness of the shell of the tube during the enlarging process, the entire blank can be transformed into a tube of uniform diameter from end to end. If, however, there is not a sufficient reduction in the thickness of thc shell during the process of enlargement, or if from any other cause the diverging portions of the working-faces of the rolls cannot force the rear end of the blank over the mandrel,

such portion of the metal as may remain upon the mandrel at the conclusion of the enlarging process may be out off, in which case the remaining product will be a tube of uniform size from end t0 end.

By the term barrel -shaped roll it is herein intended to include any roll the working-face of which is between two bearings, and which is so varied in its diameter that when two such rolls are placed on opposite sides of the path through which the blank travels, with their axes relatively inclined in opposite directions, theimmediately-opposed portions of their working-faces are convergent from the end into which the blank is fed Ytoward the point between the ends where the workingfaces of the rolls most nearly approach each other, and from that point are divergent to the opposite ends of the rolls. It is also to be understood that, for the purposes of theinvention, the mandrel may have its sides either ooncavely or convexly curved in the direction of its length, the only essential being that it shall have such a taper as will suitably provide for the amount of reduction in the thickness of the shell to be produced by the compression of the shell upon the surface of the mandrel.

Vhat is claimed as the invention is- 1. The improvement in the art of transforming solid steel or iron ingots'or blanks into tubes of prescribed internal and external diameter herein described, which consists in iirst progressively developing a tubular formation in a suitably-heated steel or iron blank by means of the action upon it of the converging portion of the workingfaces of diagonally-acting barrel-shaped rolls so proportioned and adjusted as to the relatively opposite angles of inclination of their axes and as to the angles of convergence of the portions of their working-faees,which act preliminarily upon the blank, as to rupture the blank along the line of its axis and induce aspirally-outward movement of the metal from the center of the blank, and then, secondly, progressively compressing, and at the same time forcing forward, the shell of the tubular formation thus developed over the surface of aconical or conoidal mandrel by means of the eX- ternal action upon the blank of the diverging portion of the working-faces of the said barrel-shaped rolls, between which diverging portions ot' the rolls the conical or conoidal mandrel is interposed, whereby at a single passage between the rolls a suitably-heated iron or steel blank is transformed into a tube the external diameter of which is greater than the width of the narrowest part of the space between the working-faces of the rolls.

2. In apparatus for transforming solid steel or iron blanks into tubes, diagonally-acting barrel-shaped rolls so arranged with relation to each other that the portions of their working-faces which first act upon the blank have convergent lilies of impingement thereon,for

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the purpose of fully developing atubular forthereby enlarging the internal and external mation in the portion of the blank upon which diameter of said tubular formation to a pre- [o they aet, and have the remaining portions of scribed extent.

their Working-faces divergent and combined f T T with an interposed conical or conoidal man- MA MABNESMABN' drel for the purpose of progressively com- Witnesses: pressing the shell of the tubular formation M. L. ADAMS,

upon the surface of the said mandrel, and A. M. JONES. 

